Evaluation and analysis of source liners and ejected materials from an electrothermal plasma discharge

Summary form only given. Electrothermal plasma sources operating in the confined controlled arc discharge regime generate plasmas which can be used for a wide variety of applications, including materials deposition, mass acceleration devices, and high heat flux material exposure. Such plasmas are produced by capillary arc discharges-discharging high voltage across an insulated sleeve. Energy radiated to the walls of the insulated sleeve is absorbed by the material surface, ablating the material and forming a dense vapor. This vapor ionizes and forms a plasma which acts as a blackbody radiation source, which in turn can provide high heat flux to exposed surfaces. The generated plasma then exits the sleeve at high velocity. A substrate placed at the exit of the sleeve can act as a deposition surface for the ablated material. The electrothermal plasma source PIPE produces high density plasmas with heat fluxes on the order of gigawatts per square meter over periods of hundreds of microseconds. Sleeves of different materials can be machined and outfitted to the device, changing the composition of the plasma produced by their ablation. In addition, these sleeves can provide material surfaces for investigation of high heat flux plasma exposure. Thermal conductivity, ionization energy, and heat of vaporization are important material qualities of these sleeves when predicting the characteristics of produced plasmas. The high heat flux plasmas produced in the PIPE device have been exposed to various materials, including polycarbonate Lexan and elemental tungsten. The plasma exiting the PIPE device has been characterized by a range of optical techniques and compared to predicted characteristics. Electron temperature estimations and density measurements have been investigated with spectroscopic techniques. Spectral analysis has been performed to investigate dissociation of the plasma material. Velocity measurements of ejected plasma have been taken with high speed cameras. Material which is ablated or otherwise eroded is ejected from the device and collected on a substrate outside the device exit. Total ejected material has been determined by weight comparison of pre-and post-discharge insulating sleeves. Characteristics of the ejected material have been investigated with SEM and EDS techniques. Homogeneity and surface qualities of the redeposited material were investigated.